docs(agents): tooling-improvement and architecture-upkeep rules; add tool tests

Researched the sibling project's tooling discipline (tools/README inventory,
tools/tests with stdlib unittest, check_docs gate, clean-worktree rule, paid-API
tools human-triggered) and encoded it for this repository:

AGENTS.md gains two sections.
- 'Python and shell tooling': fix the tool not the artefact; improve over fork;
  one script one job; fail loudly; result files for Unreal commandlets; absolute
  paths into sandboxes; clean worktree for generators (.blend/.umap are
  read-only on checkout); network/paid tools human-triggered with 429 back-off;
  measure don't assert; document every tool in the README inventory; test the
  pure parts.
- 'Architecture documentation': Docs/Architecture is arc42 in Markdown; a table
  mapping each kind of change to the section that must be updated; describe what
  exists, ADRs append-only, keep architecture.md in sync, prettier --check.

Made the referenced scaffolding real rather than aspirational:
- Tools/tests/ (README + __init__) with 12 passing unittest tests covering
  input_emulation's ioctl/key-code encoding and block_height_report's height
  classification.
- requirements-tools.txt (requests).
- Extracted classify_height() out of block_height_report.main() so the roof/
  shelter rule is testable — the rule itself came from the v0.1.2 finding.
- Tools/README: tests section, input-injection rows, and the removed TEMP-QA row
  replaced by the real cvar/self-test description.
- Docs/Architecture 05 + architecture.md: tools table extended (input injection,
  tests) and a link to the tool rules; kept in sync per the new rule.

Tools/tests/test_block_height_report.py

@@ -0,0 +1,53 @@
+"""Tests for Geo/tools/block_height_report.py::classify_height.
+
+The Geo tools live outside `Tools/`, so the test adds `Geo/tools` to `sys.path`
+before importing the module by name.
+"""
+
+import os
+import sys
+import unittest
+
+ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", ".."))
+sys.path.insert(0, os.path.join(ROOT, "Geo", "tools"))
+
+import block_height_report as bhr  # noqa: E402
+
+
+class ClassifyHeightTest(unittest.TestCase):
+    def test_height_tag_wins(self):
+        height, source = bhr.classify_height({"building": "yes", "height": "18.1"})
+        self.assertEqual(height, 18.1)
+        self.assertEqual(source, "height tag")
+
+    def test_height_tag_beats_levels(self):
+        height, _ = bhr.classify_height(
+            {"building": "yes", "height": "12.5", "building:levels": "4"})
+        self.assertEqual(height, 12.5)
+
+    def test_levels_derive_height(self):
+        height, source = bhr.classify_height(
+            {"building": "yes", "building:levels": "4"}, level_height=3.2)
+        self.assertEqual(height, 12.8)
+        self.assertIn("levels x", source)
+
+    def test_roof_is_not_a_building_volume(self):
+        # building=roof at layer=1 is an elevated canopy, not a two-storey block.
+        height, source = bhr.classify_height({"building": "roof", "layer": "1"})
+        self.assertEqual(height, 0.0)
+        self.assertIn("not a building volume (roof)", source)
+
+    def test_transit_shelter_is_not_a_building_volume(self):
+        height, source = bhr.classify_height(
+            {"building": "yes", "amenity": "shelter", "shelter_type": "public_transport"})
+        self.assertEqual(height, 0.0)
+        self.assertIn("not a building volume (shelter)", source)
+
+    def test_missing_data_falls_back_to_a_flagged_guess(self):
+        height, source = bhr.classify_height({"building": "yes"})
+        self.assertEqual(height, 2 * bhr.LEVEL_HEIGHT)
+        self.assertTrue(source.startswith("GUESS"))
+
+
+if __name__ == "__main__":
+    unittest.main()